Wireless roaming up to 400ft line of sight, 180 ft in a typical office. Flexible microphone boom arm. Noise canceling mic. 64 bit encryption DECT Security Certified. Conference additional 3 Savi 7200 series headsets for conference or training calls. Connection : wireless DECT technology, No Wi-Fi interference. 12 hours talk time on a single charge (50 hours of standby). 3 hour charge time. SoundGuar protects against sound levels above 118 dBA. Anti-startle detects and eliminates any large sudden increase in signal level. Headset weight 138 g. Remote answering with lifter (HL10) or electronic hook switch module (EHS), sold separately. Sold by each.